Conventional commerical television (TV) cameras, specifically those of the vidicon type, generate a raster on the target by deflecting an electron beam horizontally at a fast rate (15,275 times per second) and vertically at a slower rate. In order to decrease flicker, prior art arrangements have produced an interlaced pattern of scanning.
As a result, conventional TV cameras obtain 525 lines of resolution by scanning half that number in a first field and an identical number in an interlaced second field. Precise positioning of the interlaced lines is accomplished by precise timing between the vertical drive signals and the horizontal drive signals.
In certain applications, such as in television viewing of a microscopically magnified image of an object, extremely good resolution--above and beyond that provided by coventional TV cameras--is required. Thus, the technology of the prior art is inadequate to provide such highly improved resolution, and there is a need in the prior art for an arrangement by means of which television scanning with highly improved resolution can be achieved.
In the latter regard, the following patents typify the prior art in this area of technology: U.S. Pat. Nos. 3,136,847; 3,422,223; 3,914,543; 4,331,980; 4,364,090; 4,498,106; 4,506,298; 4,513,312; 4,558,347; 4,580,170; and 4,602,273. None of these patents discloses a vertical drive modifier circuit as disclosed herein for performance of television scanning with improved resolution.